Minimally-invasive medical procedures are used to deploy prostheses such as stent grafts into the human or animal body. These procedures use a deployment device which is introduced into a vessel such as a blood vessel using the Seldinger technique to deliver a stent graft on the deployment device along a blood vessel to a selected site. A selected site may be a portion of the human or animal vasculature which is damaged or ruptured and the procedure is arranged to deploy a stent graft, effectively a tubular body, across the damaged portion of the vasculature to provide an alternative blood flow path.
In many cases it is not only important to get the longitudinal position of a stent graft in the vasculature in the correct position but it is also important to be able to place the stent graft accurately in a rotational position.
During advancement of a delivery device through the vasculature it is often necessary for the physician to rotate the delivery device to encourage the nose cone dilator at the proximal end of the device to track a previously inserted guide wire so that by the time the delivery device is at a selected position in the vasculature the exact rotational position of the device may not be fully known.
Knowledge of the rotational position is particularly useful for instance for when there is a branch vessel and the stent graft is to be placed so that the branch vessel is not occluded. The stent graft may for instance have a side arm which extends to the branch vessel or a fenestration or scallop which must be correctly placed in the rotational as well as longitudinal position to avoid exclusion of the side arm.
In general delivery devices are constructed with as plain a cross section as possible, such as a circular cross section, to provide minimal obstruction during advancement of a delivery device through the vasculature and damage to the vasculature of a patient during the procedure.
It is the object of this invention to provide a endovascular delivery device with a relatively simple arrangement which will enable a physician to determine the rotational position of a delivery device and hence a stent graft carried on the delivery device.
Throughout this specification the term distal with respect to a portion of the aorta a deployment device or a prosthesis means the end of the aorta deployment device or prosthesis further away in the direction of blood flow from the heart and the term proximal means the portion of the aorta deployment device or end of the prosthesis or stent graft nearer to the heart. When applied to other vessels similar terms such as cordal and cranial should be understood.